Inkjet printing mechanisms use pens which shoot drops of ink onto a page or sheet of a print medium. Each pen has a printhead formed with very small nozzles through which the ink drops are fired. To print an image, the printhead moves back and forth across the page shooting ink drops as it moves. Inkjet printing mechanisms may be included in a variety of different devices, such as inkjet printers, plotters, scanners, facsimile machines, or other devices, all of which are referred to collectively herein as "inkjet printers." The print medium is typically a sheet material, such as paper, mylar, foils, transparencies, card stock, etc., but for convenience the term "paper" is used herein for purposes of illustration.
Inkjet printers typically require the pen cartridges or ink lines to be primed, such as after periods of inactivity, or upon replacement of the ink supply. The act of priming forces ink from the supply reservoir through the nozzles to ready the printer for printing. While some printing systems use complicated electrically operated pumping mechanisms, such as peristaltic pumps, these pumping systems typically increase the power consumption of the inkjet printer. Moreover, these automatic systems are often costly, complicated, and occasionally subject to failure, if not in the mechanical pump portion, then in the control functions. The automatic pump and motor systems also increase the weight of the overall printing unit.
Thus, there is a need for a simple and efficient priming system, which is lightweight, easy to assemble, and which may be used without increasing the power drain on the printer. Such a priming apparatus would be particularly useful for a printer which has only occasional use, such as a printer for the home environment, or for a backup or portable unit.